Background: The calibration of the dosimetric instruments is a basis of safety of the people working with the ionization radiation. The necessity of calibration is especially important in the institutions where the open radioactive sources are used. The paper presents the abilities of CLOR's radiological protection instruments calibration facility and the important conclusions from calibrations results for group of instruments used in Nuclear Medicine Department in Poland.
Materials and methods: The results for five types of instruments dedicated for dose rate as well as for contamination measurements were presented. Analyzes were based on the results presented at calibration certificated of chosen instruments.
Results: It has been shown that the calibration factor might fluctuate by 50% in period of one year for particular instrument as well as for more than 100% for two instruments of the same type.
Conclusions: The presented results prove the importance of the calibration process and it is evidence that the calibration process of the radiation protection instruments should be performed periodically for the test of dose rate measurements as well as for contamination measurements abilities.
Keywords: calibration factor; nuclear medicine; radiological protection instruments.